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Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
MCA Integrated SEMESTER VIII EXAMINATION SUMMER 2019
Subject Code:4480603 Date: 08-05-2019
Subject Name: Network Security
Time: 10:30 AM TO 1:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1

Answers the following:
1. Give one major difference between a passive and an active attack.
2. What is a clear signed message in SMIME?
3. Explain Relative Prime Number.
4. Define Dual signature.
5. What is a honey pot?
6. Explain Stateful firewall.
7. Explain Salt in password management.
07

1. What is traffic padding and what is its purpose?
2. Mention and very briefly explain any three design features/parameters considered while designing the symmetric block cipher.
3. Describe the usefulness of Handshake protocol in SSL
02
03
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Q.2

Why mode of operation is defined? Explain any two cipher block modes of operations.
07

1. Mention and very briefly explain any five fields/elements of the format of X.509 Public Key Certificate.
2. Just by using a schematic diagram, show how authentication can be achieved in public key cryptography. Assume that confidentiality is not required.
05
02
OR

1. Write two important advantages of public key cryptography over shared secret key based cryptography
2. How MAC is calculated using one-way hash function?
3. Write what is ciphertext only attack in brief.
03
03
01
Q.3

Explain PGP Services.
07

1. Write any four important differences between Kerberos version 4 and 5.
2. What is the need for using both, symmetric and asymmetric keys in construction of Enveloped Data?
04
03
OR
Q.3

Briefly explain the structure/format indicating the different fields of Private Key Ring in PGP.
07

Briefly explain how the authentication service is provided in distributed environment using Kerberos.
07
Q.4

Draw ESP format for IPsec and show the need of fields SPI, sequence number, payload data, padding, pad length, next header and authentication data field.
07
2

1. What is the difference in message authentication code calculation process in SSL and TLS?
2. What is the role of function in TLS?
3. Write full form of ESP.
03
03
01
OR
Q.4

What is IPSec? What are the applications of IPSec? Explain the modes of IPSec operations.
07

1. Why web security is more important issue today? List at least four reasons for the same.
2. Write the steps taken by SSL to calculate master secret.
3. What does the ChangeCipherSpec protocol do?
04
02
01
Q.5

Explain how attacks like IP address spoofing, source routing and tiny fragments can be carried out on packet filtering routers? What are the counter measures?
07

1. Explain: Rule based Intrusion Detection.
2. What do you mean by false positive and false negative in Intrusion Detection System?
05
02
OR
Q.5

Explain the need of Firewall. Explain different types of Firewalls in detail.
07

1. What is an Audit record in IDS.
2. How Unix manages passwords to make it secure from attackers?
3. Explain how one can use Markov model for proactive password checking.
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03
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